The increasing memory densities of memory disk drive devices such as hard disk drives has necessitated very strict levels of cleanliness in that the interior of the drives must be free of dirt as well as ion contamination and outgassing from the materials of the various components. A characteristic demanded of the internal components is the flammability standard UL 94 V-0, and a polybutylene terephthalate (PBT) material containing a phosphorus-based flame retardant has previously been used to satisfy this characteristic. Outgassing caused by this flame retardant, however, has been a problem.
For the housing of a memory disk drive device, a resin housing has been known in which a resin material, such as a polyimide (hereafter abbreviated PI), polyamide imide (hereafter abbreviated PAI), polyether ether ketone (hereafter abbreviated PEEK), polyphenylene sulfide (hereafter abbreviated PPS), or liquid crystal polymer (hereafter abbreviated LCP) resin, contains carbon fibers and/or inorganic fiber as a filler (see Patent Document 1).
For the configuration of an insulating bushing incorporated inside a memory disk drive device, an insulating bushing has been known in which a cylindrical member is disposed so as to cover the inside of a lead-out hole formed in a fixing member for fixing a stator of a motor (see Patent Document 2).
As means of reading and writing data in a memory disk drive device, a swing-type hard disk carriage has been known which reads and writes data at an arbitrary track position by causing a swing arm provided with a pickup magnetic head to move radially to the surface of a disk (see Patent Document 3). This hard disk carriage has a ring voice coil and a concave part disposed in a predetermined location of a molding resin for sealing together the voice coil and the carriage components, and having a hardened molten material of high specific gravity packed into the concave part to function as a balancer.
A ramp for a hard disk drive has been known as a resin component for retracting a pickup magnetic head for a memory disk drive device when the disk is stopped. For this resin component, a polyoxymethylene resin ramp for a hard disk drive has been known in which a polyoxymethylene resin contains an inorganic pigment selected from among a group consisting of zinc oxide, titanium oxide, metal complex oxides, iron oxide, ultramarine, cobalt blue, calcination pigments, carbon black, acetylene black, and lamp black, and has an outgassing level of 20 μg/g or less and harmful components in the outgas of 0.3 μg/g or less (see Patent Document 4).